Field of the Invention
The present invention relates to an image forming apparatus for improving a power saving effect, and a control method thereof.
Description of the Related Art
Conventionally, an image forming apparatus such as a printing apparatus for printing and outputting data can be normally operated with a power state of the apparatus set to a sleep state (a power saving state) in which power supply to unused portions is stopped in order to realize power saving. In the sleep state, it is required that the power state of the apparatus periodically returns to a normal state (a non-power-saving state) from the sleep state for the purpose of detecting the operation of a touch panel or the pressing of a key, or for the purpose of a periodic communication process with a server. In general, compared to the periodic communication process with the server, it is required that the power state of the apparatus returns to the normal state in a short interval (for example, 200 ms) in order to appropriately detect the operation of the touch panel or the key. Accordingly, a time interval for periodical transition from the sleep state to the normal state is generally set to an appropriate fixed value on a condition that the operation of the touch panel or the key is detected. Therefore, frequent release of the sleep state deteriorates the effect of power saving.
However, depending on the configuration of the apparatus, when the time interval for returning the power state of the apparatus to the normal state from the sleep state is uniformly set to a fixed value, the frequency of the return to the normal state may be increased more than necessary. For example, in the conventional image forming apparatus, there is known an apparatus which includes only physical operational keys and LEDs without a display panel. Such an apparatus can generally instruct the setting of the apparatus and display the state of the apparatus, using a UI application operating on a PC (personal computer).
In this way, in the case of the apparatus having no display panel, particularly the number of operational keys is small, so that all the keys can be assigned to interruption ports. In such a case, there is no need to cause the power state of the apparatus to transition from the sleep state to the normal state only for detecting a key pressing. In this case, the time for the return to the normal state is necessarily set to an appropriate value paying attention to a periodic communication process with the server. At that time, the appropriate value is changed depending on a setting by a user or a communication status of the apparatus with the server. Accordingly, the apparatus transitions to the normal state at an unnecessary timing only by setting the time interval to a fixed value, which may disable to achieve a power saving effect.
By the way, Japanese Laid-Open Patent Publication (Kokai) No. 2012-108032 discloses a technique of setting a shorter time taken for complete discharge as a time for the return from a power saving mode, based on a remaining amount of a secondary battery and a discharge current value. However, in this technique, the setting value for the return is a fixed value and is not set taking a status of use of a network into consideration, which may further improve the power saving effect.